He is known for novels and short stories, and as a poet and playwright. His early years in what he frequently describes as a Jewish ghetto in the East End of London made him very conscious of his Jewish identity. Litvinoff chronicled these early years in what is perhaps his best-known work, Journey Through a Small Planet.

Litvinoff is also well known for being one of the first to raise publicly the implications of T. S. Eliot's negative references to Jews in a number of poems, a controversy that continues, in his famous poem To T. S. Eliot. This protest against T. S. Eliot on the subject of anti-Semitism took place at an inaugural poetry reading for the Institute of Contemporary Arts in 1951. Litvinoff, an admirer of Eliot, was appalled to find Eliot republishing lines he had written in the 1920s about 'money in furs' and the 'protozoic slime' of Bleistein's "lustreless, protrusive eye" only a few years after the Holocaust, in his Selected Poems of 1948. When Litvinoff got up to announce the poem at the ICA reading, the event's host, Sir Herbert Read, declared, "Oh Good, Tom's just come in," referring to Eliot (Thomas Stearns, nickname: Tom). Despite feeling "nervous", Litvinoff decided that "the poem was entitled to be read" and proceeded to recite it to the packed but silent room:

So shall I say it is not eminence chillsbut the snigger from behind the covers of history,the sly words and the cold heartand footprints made with blood upon a continent?Let your wordstread lightly on this earth of Europelest my people’s bones protest.

In the pandemonium after Litvinoff read the poem, T. S. Eliot stated, "It's a good poem, it's a very good poem."

In the 1950s, on a rare Western visit to Russia with his wife, Cherry Marshall, and her fashion show, Litvinoff became aware of the plight of persecuted Soviet Jews, and started a world campaign against this persecution. One of his methods was editing the newsletter Jews in Eastern Europe and also lobbying eminent figures of the twentieth century such as Bertrand Russell, Jean-Paul Sartre, and others to join the campaign. Due to Litvinoff's efforts, prominent Jewish groups in the United States became aware of the issue, and the well-being of Soviet Jews became a worldwide campaign.